CodeGenTBAA.h revision b22c7dc707cf3770ff3b5e5f11f11fd0aaa06d9b 
1//===--- CodeGenTBAA.h - TBAA information for LLVM CodeGen ------*- C++ -*-===//
2//
3//                     The LLVM Compiler Infrastructure
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9//
10// This is the code that manages TBAA information and defines the TBAA policy
11// for the optimizer to use.
12//
13//===----------------------------------------------------------------------===//
14
15#ifndef CLANG_CODEGEN_CODEGENTBAA_H
16#define CLANG_CODEGEN_CODEGENTBAA_H
17
18#include "clang/Basic/LLVM.h"
19#include "llvm/MDBuilder.h"
20#include "llvm/ADT/DenseMap.h"
21
22namespace llvm {
23  class LLVMContext;
24  class MDNode;
25}
26
27namespace clang {
28  class ASTContext;
29  class CodeGenOptions;
30  class LangOptions;
31  class MangleContext;
32  class QualType;
33  class Type;
34
35namespace CodeGen {
36  class CGRecordLayout;
37
38/// CodeGenTBAA - This class organizes the cross-module state that is used
39/// while lowering AST types to LLVM types.
40class CodeGenTBAA {
41  ASTContext &Context;
42  const CodeGenOptions &CodeGenOpts;
43  const LangOptions &Features;
44  MangleContext &MContext;
45
46  // MDHelper - Helper for creating metadata.
47  llvm::MDBuilder MDHelper;
48
49  /// MetadataCache - This maps clang::Types to llvm::MDNodes describing them.
50  llvm::DenseMap<const Type *, llvm::MDNode *> MetadataCache;
51
52  /// StructMetadataCache - This maps clang::Types to llvm::MDNodes describing
53  /// them for struct assignments.
54  llvm::DenseMap<const Type *, llvm::MDNode *> StructMetadataCache;
55
56  llvm::MDNode *Root;
57  llvm::MDNode *Char;
58
59  /// getRoot - This is the mdnode for the root of the metadata type graph
60  /// for this translation unit.
61  llvm::MDNode *getRoot();
62
63  /// getChar - This is the mdnode for "char", which is special, and any types
64  /// considered to be equivalent to it.
65  llvm::MDNode *getChar();
66
67  /// CollectFields - Collect information about the fields of a type for
68  /// !tbaa.struct metadata formation. Return false for an unsupported type.
69  bool CollectFields(uint64_t BaseOffset,
70                     QualType Ty,
71                     SmallVectorImpl<llvm::MDBuilder::TBAAStructField> &Fields,
72                     bool MayAlias);
73
74public:
75  CodeGenTBAA(ASTContext &Ctx, llvm::LLVMContext &VMContext,
76              const CodeGenOptions &CGO,
77              const LangOptions &Features,
78              MangleContext &MContext);
79  ~CodeGenTBAA();
80
81  /// getTBAAInfo - Get the TBAA MDNode to be used for a dereference
82  /// of the given type.
83  llvm::MDNode *getTBAAInfo(QualType QTy);
84
85  /// getTBAAInfoForVTablePtr - Get the TBAA MDNode to be used for a
86  /// dereference of a vtable pointer.
87  llvm::MDNode *getTBAAInfoForVTablePtr();
88
89  /// getTBAAStructInfo - Get the TBAAStruct MDNode to be used for a memcpy of
90  /// the given type.
91  llvm::MDNode *getTBAAStructInfo(QualType QTy);
92};
93
94}  // end namespace CodeGen
95}  // end namespace clang
96
97#endif
98